[substrate exposure apparatus and method]

ABSTRACT

A substrate exposure apparatus, having a line light source and a control system. The line light source has several point light sources. The control system converts the pattern into a timing signal to control the light status and dark status of each point light source. The control system also controls a scan light source to radiate the photoresist on the substrate, so that the photoresist is exposed. Further, in a substrate exposure method, multiple point light sources are arranged as at least one line light source to scan the photoresist once or several times to obtain a better resolution of the pattern transferred to the photoresist.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional application of, and claims thepriority benefit of, U.S. application Ser. No. 10/064,208 filed on Jun.21, 2002, which claims the priority benefit of Taiwan application serialno. 90130498, filed Dec. 10, 2001.

BACKGROUND OF INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates in general to a substrate exposureapparatus and method, and more particularly, to a substrate exposureapparatus and method that does not require a photomask for transferringa pattern to the photoresist.

[0004] 2. Description of the Related Art

[0005] Photolithography process is one of the crucial steps in the printcircuit board, the substrate and the semiconductor fabrication process.In wafer fabrication, the patterned and doped regions for each thin filmlayer are determined by photolithography process. Additionally, theformation of metal film patterns in the print circuit board and thesubstrate are determined by the photolithographic process. For each one,the photomask must be well prepared. In the photolithographic process,after some preparation procedures, the photomask is coated on thesubstrate, and then a soft baking and a hard baking proceses are furtherperformed. After the photoresist on the wafer is cured, the steps ofexposure and development are performed to transfer the pattern of thephotomask to the photoresist.

[0006] Referring to FIG. 1, a conventional photolithography process thatuses a contact mode photomask to transfer the pattern to the photoresistis schematically shown. A substrate 100, on which circuit, dielectriclayer, dielectric pattern or conductive layer may have been formed, isprovided. A photoresist 102 is formed on the substrate 100. A photomask110 is disposed on the photoresist 102. To protect the surface of thephotomask 110, a protect film 104 is placed between and separates thephotomask 110 and the photoresist 102. The protect film 104 is incontact with both the surface of the photomask 110 and the photoresist102. By radiation of a light source 112, an exposure step is performedon the photoresist 102, so that the pattern of the photomask 110 istransferred to the photoresist 102.

[0007] The conventional contact mode photomask 110 includes formation ofa patterned blocking layer 108 on a surface of a transparent substrate106. To protect the photomask 110, the protect film 104 sandwichedbetween the photomask substrate 106 and the photoresist 102 is incontact with both surfaces of the photomask substrate 106 and thephotoresist 102. The patterned blocking layer 108 of the photomask 110blocks the light source 112 to determine the pattern on the photoresist102 to be radiated.

[0008] Referring to FIG. 2, a conventional photolithography processusing a non-contact mode photomask to transfer a pattern to aphotoresist is schematically shown. A substrate 200 on which aphotoresist 202 is formed is provided. Circuits, dielectric layers,dielectric patterns or conductive layers may have been formed on thesubstrate 200. A photomask 210 is located above the photoresist 202. Alens set 214 is disposed between the photomask 210 and the photoresist202. By radiation of a light source 212, the photoresist 202 is exposed,and the pattern of the blocking layer 208 on the photomask 210 istransferred as the pattern 216 on the photoresist 202.

[0009] The conventional non-contact mode photomask is constructed byforming the patterned blocking layer 208 on a transparent substrate 206.The patterned blocking layer 208 on the transparent substrate 206 blocksthe light source to determine the pattern of the photoresist 202 to beradiated. In a non-contact mode, the pattern of the photomask 210 istransferred to the photoresist 202 by the lens set 214. The fabricationof the conventional photomask is very time consuming and costly. Thephotomask has to be kept in an appropriate environment, and themaintenance cost is also high.

[0010] In addition, the pattern of the photomask cannot be modified.When the circuit design of the wafer or printed circuit board requires amodification, a new photomask has to be fabricated.

SUMMARY OF INVENTION

[0011] The present invention provides a substrate exposure apparatus andmethod that does not require a photomask. The fabrication cost andmaintenance cost of a photomask in the photolithography process are thussaved.

[0012] The substrate exposure apparatus provided by the presentinvention comprises a scan light source and a control system. The scanlight source is located over the photoresist to be exposed on thesubstrate. The control system controls the scan light source or thesubstrate to shift along a scan path, and converts the pattern to beformed on the photoresist into a timing signal, so as to control thelight and dark status of the scan light source at different times.

[0013] In the above substrate exposure apparatus, the scan lightcomprises multiple point light sources. The point light sources arearranged in a single file such as a line light source. Alternatively,the point light sources can be arranged in multiple files such asmultiple line light sources. The line light sources are parallel to eachother. Along the aligning direction of each line light source, there isa specific position shift for each of the line light sources, so thatthe point light sources in one line light source are staggered with thepoint light sources in another line light source. As a result, theexposure resolution is enhanced. The above point light sources includelight emitting diodes and laser diodes.

[0014] In the substrate exposure apparatus of the present invention, thelight of the scan light source is adjusted by a lens set to radiate thephotoresist for exposure.

[0015] In the present invention, a substrate exposure method isprovided. The substrate exposure method uses a scan light source and acontrol system to perform exposure on a photoresist on a substrate. Thescan light source is located above the photoresist. The control systemcontrols the scan light source or the substrate to shift along a scanpath. The pattern to be transferred to the photoresist is converted intoa timing signal to control the light and dark status of the scan lightsource, so as to perform exposure on the photoresist.

[0016] In the above substrate exposure method, the scan path of the scanlight source is vertical to the aligning direction of the point lightsources.

[0017] In the above substrate exposure method, the scan path of the scanlight does not have to be vertical to the aligning direction of thepoint light sources.

[0018] Both the foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

[0019]FIG. 1 is a schematic drawing of a conventional photolithographyprocess to transfer a pattern from a contact mode photomask to aphotoresist.

[0020]FIG. 2 is a schematic drawing of a conventional photolithographyprocess to transfer a pattern from a non-contact mode photomask to aphotoresist.

[0021]FIG. 3 is a schematic drawing for forming a pattern on aphotoresist using point light sources aligned into a single line in oneembodiment of the present invention.

[0022]FIG. 4 is a schematic drawing for forming a pattern on aphotoresist using point light sources aligned into multiple lines in oneembodiment of the present invention.

[0023]FIG. 5 is a schematic drawing of a scan path on the photoresistusing point sources aligned into multiple lines in one embodiment of theinvention.

[0024]FIG. 6 is a schematic drawing of multiple scan paths forperforming multiple scans on the photoresist using point light sourcesaligned into a signal line in one embodiment of the invention.

[0025]FIG. 7 is a schematic drawing of multiple scan paths forperforming multiple scans on the photoresist using point light sourcesaligned into a signal line in another embodiment of the invention.

DETAILED DESCRIPTION

[0026] Referring to FIG. 3, a schematic drawing for forming a pattern ona photoresist using point light sources arranged in a single line isshown. Before performing the exposure process, a substrate 300 with aphotoresist 302 formed thereon is provided. Circuits, dielectric layers,dielectric patterns or conductive layers may have been formed on thesubstrate 300. The substrate 300 is disposed in a chaise 316. Thesubstrate 300 includes a wafer, a printed circuit board or various typesof package substrates. The substrate exposure apparatus comprises a scanlight source 304 and a control system 308. The scan light source 304comprises multiple point light sources 306 arranged in a single filesuch as a line light source 304 along an aligning direction 318. Thepoint light sources 306 comprise light emitting diodes or laser diodes.The control system 308 controls the chaise 316 that carries thesubstrate 300 to move along the substrate shifting direction 314. By thecontrol system 308, a pattern 312 to be transferred to the photoresist302 is converted into a timing signal which controls the light and darkstatus of the scan light source 304 at different times for exposing thephotoresist 302. In addition, a lens set 304 is located between the scanlight source 304 and the substrate 300. The lens set 310 can adjust thelight emitted from the scan light source 304 before radiating thephotoresist 302.

[0027] Further referring to FIG. 3, the substrate 300 in the chaise 316is shifted along the substrate shifting direction 314. The controlsystem 308 decodes the pattern to be transferred to the photoresist 302into a one-dimensional light spot-to-time signal. Such one-dimensionaltiming signal controls the light and dark status for each point source306 of the scan light source 304. As the substrate 300 is shifted alongthe substrate shifting direction 314, a relative motion between thesubstrate 300 and the scan light source 304 is produced. Therefore, thelight and dark status of the scan light source 304 at different timesdetermines whether various positions of the photoresist 302 are exposedor not. After the scan of the scan light source 304, the two-dimensionalpattern 312 is transferred to the photoresist 302.

[0028] Referring to FIG. 4, a schematic drawing of forming a pattern onthe photoresist using multiple lines of point light sources is shown.Before performing the exposure process, the substrate 300 with aphotoresist 302 formed thereon is provided. Circuits, dielectric layers,dielectric patterns or conductive layers may have been formed on thesubstrate 300. The substrate 300 is disposed in a chaise 316. Thesubstrate exposure apparatus comprises a scan light source 304 and acontrol system 308. The scan light source 304 comprises multiple pointlight sources 306 arranged in multiple parallel line light sources 304a, 304 b, 304 c, 304 d with an aligning direction 318. A position shiftS along the aligning direction 318 for the line light sources 304 a, 304b, 304 c and 304 d allows the point sources 306 in each of the linelight sources 304 a, 304 b, 304 c and 304 d to be staggered, so as toenhance the exposure resolution.

[0029] The substrate 300 carried by the chaise 316 is shifted along thesubstrate shifting direction 314. The control system 308 converts thepattern to be transferred to the photoresist 302 into a timing signal tocontrol the light and dark status of the scan light source 304 forexposing the photoresist 302. A lens set 310 is located between the scanlight source and the substrate 300 to adjust the light emitted from thescan light source 304 (for example, minifying, magnifying, focusing anddefocusing the pattern) before radiating the photoresist 302.

[0030] Further referring to FIG. 4, the substrate 300 in the chaise 316is shifted along the substrate shifting direction 314. The controlsystem 308 decodes the pattern to be transferred to the photoresist 302into a one-dimensional light spot-to-time signal. Such one-dimensionaltiming signal controls the light and dark status for each point source306 of the scan light source 304. As the substrate 300 is shifted alongthe substrate shifting direction 314, a relative motion between thesubstrate 300 and the scan light source 304 results. Therefore, thelight and dark status of the point sources 306 in each line light source304 a, 304 b, 304 c and 304 d at different times determines whethervarious positions of the photoresist 302 are exposed or not. After thescan of the scan light source 304, the two-dimensional pattern 312 istransferred to the photoresist 302.

[0031] Referring to FIG. 5, the scan path on the photoresist usingmultiple lines of point light sources is schematically shown. It isclear from FIG. 5 that the point light sources 306 are arranged intoline light sources 304 a, 304 b, 304 c, 304 d. A position shift S alongthe direction 318 for the line light sources 304 a and 304 b, is 1/n ofthe distance P between the neighboring point light sources 306.Similarly, the position shift S exists along the direction 318 for theline light sources 304 b and 304 c, and 304 c and 304 d.

[0032] By moving the substrate 300 along the substrate shiftingdirection 314, the line light sources 304 a, 304 b, 304 c and 304 dperform exposure on the photoresist 302 along the scan direction 320.The space between each scan path 320 is the shift position S. Using theline light sources 304 a, 304 b, 304 c and 304 d as an example, theresolution of the scan light source 304 along the direction 318 isenhanced four times compared to the single line light source.

[0033] Referring to FIG. 6, the scan path for performing multiple scanson the photoresist using a single line of point light sources isschematically shown. In FIG. 4, the point light sources 306 are arrangedinto multiple line light sources 304 a, 304 b, 304 c and 304 d toimprove the resolution in the direction 318. In addition to the methodof changing the arrangement of point light sources, a better resolutioncan also be obtained by changing the scan method of the scan lightsource 304. It is clearly seen in FIG. 6 that the point light sources306 are arranged into a single line light source 304 aligned with thedirection 318. The aligning direction 318 of the single line lightsource 304 is vertical to the scan path 320. In addition, the line lightsource 304 scans the photoresist 302 along the scan path 320 multipletimes. The path for each scan is spaced from the previous scan with adistance A, where A is equal to 1/n of the pitch P of the point sources306, and n is a natural number.

[0034] Referring to FIG. 7, a scan path for scanning the photoresistseveral times using another single line of point sources isschematically shown. As shown in FIG. 7, though the photoresist 302 isexposed by multiple scans, the angle between the scan path 320 and thealigning direction 318 of the point sources 306 is not equal to 90°.Since such angle is not 90°, the distance between the neighboring scanpaths B is smaller than the pitch P of the point light sources 306.Thus, the scan resolution is also improved.

[0035] In FIGS. 6 and 7, by multiple scans and controlling the anglebetween the scan path and the aligning direction of the point lightsources unequal to 90°, the resolution is enhanced. It is appreciatedthat people of ordinary skill in the art may properly combine the abovetwo methods to obtain a further improved resolution.

[0036] In addition, in the above FIGS. 3 to 7, the shift of thesubstrate 300 is accompanied with the light and dark status control ofthe scan light source 304 at different times to perform exposure on thephotoresist 302. However, the relative motion for the photoresist 302and the scan light source 304 can also be achieved by the shift of thescan light source, the lens set 310, or even by the movement or rotationof some mirror or lens in the lens 310.

[0037] According to the above, the present invention includes at leastthe following advantages.

[0038] 1. The substrate exposure apparatus and method directly transfersthe pattern to the photoresist by scan, so that the time for fabricatingthe photomask is saved.

[0039] 2. Various patterns can be transferred to the photoresist usingthe substrate exposure apparatus and method provided by the presentinvention, while the fabrication of photomasks corresponding todifferent patterns is not required. The fabrication cost is thus greatlyreduced.

[0040] 3. The pattern is transferred to the photoresist by scan, so thatit is even easier for automatic mass production of integrated circuits.

[0041] 4. While fabricating the products, the circuit design can bemodified in a real time, so that the development time is reduced, andversatile customized designs with small quantity become possible.

[0042] 5. The relative position of the light sources and the lens set isfixed, so that the aligning position difference is fixed (not altered bychange of photomask), and the position correction is easier.

[0043] 6. The cost maintenance and preservation of photomasks can beeliminated.

[0044] Other embodiments of the invention will appear to those skilledin the art from consideration of the specification and practice of theinvention disclosed herein. It is understood that the specification andexamples are to be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

1. A substrate exposure apparatus, applicable to transfer a pattern to a photoresist on a surface of a substrate, the substrate exposure apparatus comprising: a scan light source, disposed at a position spaced from a surface of the photoresist on the substrate with a distance, and the scan light source comprising a plurality of point light sources; and a scan control system, converting the pattern into a timing signal to control light and dark status of each of the point light sources at different times, the scan control system further allows the substrate exposure apparatus to have a scan function, such that the scan light source scans the photoresist at least once along a scan path for exposure.
 2. The substrate exposure apparatus according to claim 1, wherein the substrate includes a printed circuit board.
 3. The substrate exposure apparatus according to claim 1, wherein the substrate includes a wafer.
 4. The substrate exposure apparatus according to claim 1, wherein the substrate includes various types of package substrates.
 5. The substrate exposure apparatus according to claim 1, wherein the point light sources are arranged into one line light source.
 6. The substrate exposure apparatus according to claim 1, wherein the point light sources are arranged into a plurality of line light sources.
 7. The substrate exposure apparatus according to claim 6, wherein the line light sources are parallel to each other.
 8. The substrate exposure apparatus according to claim 7, wherein the point light sources in one of the line light sources has a position shift with respect to the point light source in another line light source along an aligning direction of the point light sources, so that the point light sources are staggered to enhance the exposure resolution.
 9. The substrate exposure apparatus according to claim 1, wherein the point light sources include either light emitting diodes or laser diodes.
 10. The substrate exposure apparatus according to claim 1, wherein the scan function is achieved by shifting the scan light source.
 11. The substrate exposure apparatus according to claim 1, wherein the scan function is achieved by shifting the substrate.
 12. The substrate exposure apparatus according to claim 1, further comprising a chaise to carry the substrate.
 13. The substrate exposure apparatus according to claim 12, wherein the scan function is achieved by shifting the chaise.
 14. The substrate exposure apparatus according to claim 1, further comprising a lens set located along the optical paths between the scan light source and the substrate.
 15. The substrate exposure apparatus according to claim 14, wherein the scan function is achieved by rotating at least a component in the lens set.
 16. The substrate exposure apparatus according to claim 14, wherein the scan function is achieved by shifting at least a component in the lens set. 